Broken spokes.

My problem is that I've broken spokes in my rear wheel on my last two hard rides. The first time a baseball-sized rock caused the problem. (I think) The last time it looks like the spoke came loose at the nipple. I didn't ride as hard this last time and didn't notice it until I was cleaning my bike. I'm taking it to LBS later today, but was wondering if there was a solution other than "Buy heavy-duty rims". Like, can a qualified wheel builder arrange the spokes to be a little sturdier? Is this a common occurrance with other riders here?

I had a similar problem last year. I had been riding the same wheels for three seasons and started breaking spokes left and right. What happens is that all the tension from the spokes is forced to the elbow and the nipple during riding. The metal essentially bends back and forth a millimeter causing metal fatigue and eventually metal failure. What you probably need to do is have the entire rear wheel rebuilt with new spokes and nipples. That should solve your problem. Any LBS should do this for around $35-$40.

Like he said

Ooctrl has it right, but I'd take it a step farther. A shop with a person who specializes in wheel building can fix the problem. Not all shops employ someone who has the knowledge to do the job right.

The issue is that the wheel has to be true *and* have balanced spoke tension for it to be durable. Once the spoke tensions get out of whack relative to each other, they will start to break, as you are experiencing. Loose spokes or bent spokes are not going to last even for a light rider.

I've built a small number of wheels. Not claiming that makes me an expert, but since I invested in a spoke tensiometer and learned how to use it, my wheels last much longer. People who are more experienced than me state that the reason that hand-built wheels can be more durable than machine built is that an experienced human builder does a better job of trading off wheel trueness vs even spoke tension.